OpenVAS
OpenVAS (openvas.org) is a scanner tool that has both port scanning and vulnerability scanning functionality.
- an open-source vulnerability scanner
- originally developed from the Nessus codebase at the point where Nessus became commercial software
- managed by Greenbone (greenbone.net)
- aka Greenbone Security Assistant
- developed to be used on Linux

How it Works
- Can use from command line or a GUI version called Greenbone
- Can conduct a port scan on a target then attempt to determine what services and which versions are running on any ports it finds open
- Generates a report with a specific list of possible vulnerabilities for a given device